Water-circulating system for boilers.



' A. E. AXLUND. WATER GIRGULATING SYSTEM FOR BOILERS.

APPLICATION FILED JUNE 25, 1912.

Patented Feb. 17, 1914.

WITNESSES:

5 M. avw QLO W M j ANDREW EMANUEL AXLUND, 0F VALLEJO, CALIFORNIA.

WATER-CIRCULATING SYSTEM FOR BOILERS.

Specification of Letters Patent.

Patented Feb. 17, 1914.

Application filed June 25, 1912. Serial No. 705,708.

To all whom it may concern Be it known that I, ANDREW E. AXLUND, a citizen of the United States, residing at Vallejo, in the county of Solano and State of California, have invented new and useful Improvements in Tater-Circulating Systems for Boilers, of which the following is a specification.

The present invention relates to improvements in boilers, and particularly to a water circulating system for the same.

It is among the objects of my invention to obtain an increased or more rapid circulation of water in the boiler, which circulation will tend to revent scalin to increase evaporation, assist'ln ebullition and serve to reduce flue temperature. The system also tends to eliminate deteriorating expansion strains and give increased horse power and reduce the possibility of burning the boiler tubes.

A further object is to provide a system for obtaining a more constant circulation and increasing the rapidity with which steam may be raised by introducing steam into the tubes before lighting the fire and thus avoiding sudden movement of the boiler parts.

This invention consists in the arrangement of steam pipes in the tubes of boilers which absorb the major portion of heat from the products of combustion, and in connecting said steam pipes to a source of supply in which a higher pressure is maintained than is existent in the boiler; this means being so organized and arranged as to accelerate the circulation of water in the direction in which it tends to travel by induction.

The invention consists of the parts and the construction and combination of parts as will be hereinafter more fully described and claimed, having reference to the accompanying drawings, in which Figure 1 is a sectional detail view of a fragment of a water tube boiler. Fig. 2 is a plan view of a portion of the system.

In the drawings illustrating one embodiment of my invention, 2 represents a portion of a boiler head, from one side of which projects a series of water tubes 3, through which water will naturally circulate from the head 2 when the water in the tubes 3 is heated.

My invention essentially consists of means for accelerating the circulation of water in the boiler. This acceleration is obtained by the arrangement in all, or as many of the tubes 3 as may be desired, of injector pipes 4, which may be of suitable diameter; one end of each injector pipe terminating within the water tube 3 adjacent to the intake end of the latter. The injector pipe extends across the boiler header 2 and may project through a handhole plate 5 which is clamped by appropriate means, as a collar or flange 6, on the body of the injector pipe 4; the outer end of the latter be ing threaded, as at 7, to receive a yoke nut S which may be screwed up against a yoke 9 on the outside of the header 2.

lVhile I have shown the injector pipe 4 as extending through the outside plate of the header 2, it is to be understood that it may terminate inside of the header, but in either event it is connected to a manifold or other source of supply 10. In the manifold 10 may be fluid, as water or steam, at a pressure preferably higher than the pressure within the boiler to which the appa ratus is connected.

From the foregoing, it will be seen that in addition to the naturally induced current or circulation of water in the boiler, when communication is established between the source of high pressure 10 and the injector nozzles or pipes 4, delivering a stream of fluid from the source of supply 10 into the intake end of a boiler tube 3 will cause a more rapid circulation of water into the tube.

For the purpose of eliminating the crackling sound of the impact of steam at high pressure from the reservoir 10, when steam is used, the discharge end of the nozzle or pipe 4 may be provided with one or more apertures 11 adjacent to its end, so that during operation a small quantity of water in the boiler will be drawn into the dis charge nozzle 4, which, as stated, will eliminate noise which might otherwise possibly be produced.

Any suitable pressure-controlling valve or other appliance, as 12, may be introduced between the source of supply of high pressure 10 and the circulating nozzle or nozzles 4, as it is understood that the source of supply 10, which may be a common manifold, may be located in the most desirable position with relation to the boiler head 2.

Steam pockets, common to all boilers depending upon circulation by induction alone, are formed in the water near the heated surface. These must escape by the difference of densities of the steam and water respectively and float to the surface, thence to the steam dome proper. This is not the case in forced circulation as the rapid circulation will carry the steam pockets rapidly to the surface and release them. Because of the more rapid circulation the heat is absorbed by convection and conveyed to all parts of the boiler, thus lowering the flue temperature which is an important advantage realized by my system of water circulation. The rapid circulation of the water insures equal temperatures to all parts of the boiler; therefore strains due to expansion cannot occur to deteriorate its strength and consequently the danger of explosions is decreased.

By reason of the more rapid circulation of water and the consequent more rapid evaporation, the horse power of a boiler is increased, and as long as there is water in the boiler equipped with my forced circulating system it is impossible to burn out a boiler tube due to water coming in contact with the heated surface at all times.

Having thus described my invention, what I claim and desire to secure by Letters Patent is In a water circulating system for boilers, in combination with a boiler head and water tubes communicating therewith, an injection pipe connected to a source of pressure higher than that in the boiler which has its free end extending into an end of one of said tubes and terminating at a point a distance from the said tube end, said pipe being provided with a plurality of peripheral induction apertures which are located between the free end of the pipe and said end of the tube, whereby a part of the water which in its passage through the tube surrounds the pipe will be drawn into said apertures of the pipe.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

ANDREW EMANUEL AXLUND. lVitnesses C. BECK, DAVID E. Gnoo.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Eatents, Washington, D. G. 

